Heat coil



H. D. CURRIER HEAT COIL Filed April 1'5, 1920 n Augv 11, 1925.

Hiram E ZUZTZE'Z Patented Ang. il, i925.

OFFICE.

REHAB/ D. CURRIER, OF CHCAGO, LLINOIS', ASSGNOR T0 KELLOGG 'SWITCHBOARB AND SUPPLY COMPANY, OF CHICAGO, IIiLIlI'OlS,l A CORPORATION OF ILLINOIS.

HEAT con; I

Application filed April 15, 1920. Serial No. 374,063.

To all whom t may concern:

Be it known that I, HIRAM D. CURRIER, a citizen of the United States or America, residing in Chicago, county of Cook, and State oi' Illinois, have invented certain new and useful improvements in Heat Coils, of which the following is a speeilication.

My invention relates to thermal arresters used for the purpose of guarding againsty the injurious ei'lects of abnormal currents in electrical circuits, and an object of my invention is the provision of a device ot the class described which shall be simple and cheap to manufacture and eilicient in operation. My invention relates more particularly to a thermal unit or heat coil and is intended for use in connection with supports under spring. pressure or other apparatus, whereby the devicefo'r` a portion thereor.' is normally under stress and forms a part of the electrical circuit. The device or heat coil is adapted when operated by an abnormal current passing over the circuit'to per mit the supports or other apparatus to alter or dissever the circuit.

The heat coil of my invention comprises a resistance element adapted to be connected in the circuit and protected by a material easily weakened under the inuence oli' heat, but relatively strong under normal conditions. `When an abnormal current passesl through the resistance element, the said element becomes heated and the protective material weakened which vpermits the sup? ports or other apparatus to alter or open the circuit.

My invention is capable ot use where it is desired to altervthe .circuit automatically when the passing oi' the current therethrough is above apredetermined strength, and any material suitable Ylor the particular work in hand may be employed. rl`he resistance element of my invention is in the form of a coil of fine wire wound upon a suitable metal core suitably held in place by an easily weakened material such as any low fusing alloy or solder.

The invention further consists of novel details of construction and combination ot parts-hereinafter particularly described and pointed out in the appended specication and claims.

For a better understanding of my invention, reference may be had to the accompanying drawings in which like reference charl acters in the several views denote like part-s,

and in which- Fig. 1 is an elevation of a mounting for the arrester and illustrates the thermal device or heat coil or my invention supported thereby;

F ig. 2 is an enlarged sectional view of the heat coil and showing it resting in its supports and under conditions that are normal; K-

Fig. 3 is a view similar to that of Fig. 2 but showing the'heat coil operated after an abnormal current has Yaffected the low fusing alloy or solder.y

Figa is a disassembled perspective View oi the parts of the heatfcoil of my invention.

Referring more in detail to my invention as illustrated, and particularly to Fig. 1, I show a vertical iron plate 2 which represents that part or the distributing` frame to which the circuits entering a telephone eX- changeY are connectedl before they terminate at the exchange switchboard. A thermal unit or heat coil A is mounted and held in position on each side of the plate 2 and directly opposite each other by springs 5, 6 and 15, and springs 11, 12 and 16, respectively, which are secured to the plate 2 by the clamping screws 10. The incoming conductor 3 connects with the terminal l which is conductively connected to the spring 5` the spring 5 being connected to conductor 7 through the heat coil A and spring 6, and thence to the switchboard connections and apparatus, from whence the circuit returns by way of the conductor 8, terminal 9, clamp-- ing screws 10, which are conductively con nected to the terminal 9, and through spring 11 which is conductively connected to the clamping screws 10, through the heat coil A, spring 12 and terminal 13 which terminal 13 is conductively connected with the spring 12, to external conductor 14. The conductors 3 and 14 are therefore the two ends of the external or main circuit and the conductors 7 and 8 are the ends of the switchboard continuation. The springs 15, 6, 11 and 16 are provided with openings or slots to receive the ends oit the heat coils A and the springs 15 and 16 arLx extended or prolonged and terminate into ends 17 to hold the carbon plate protectors in position upon the ground plate extension 19. The springs 6 and 15 are separated by means of insulation to insulate them from each other and are also insulated from the plate 2 and clamping screws 10. The springs 11 and 12 are also suitably insulated in a manner just described, and the clamping screws 10 support the springs and insulating strips i'irmly in place upon the mounting plate 2.

rl`he thermal unit or heat coil A of my invention comprises a metal sleeve tube 2O having its end portion 21 turned over by means of a spinning operation. A. button 22 oic suitable insulation material is provided and is oit a size to lit in the tube 2O and when in place the said button 22 abuts against the turned over portion 21 oit the sleeve 2() which portion 21 serves as shoulder against which the button 22 rests. A stud integrally formed with the button 22 protrudes through the opening 2li lormed by the turned portion 21 of the sleeve 20 for purposes as will presently be described. A pin 25 of suitable conducting material is provided and a plug 26 of suitable insulation material is provided with a central oriiice 26 extending therethrough, and is of a size to receive the pin 25. rEhe plug 26 when in position rests against the head 27 of the pin 25 and is of a size to lit in the sleeve 2O so that when the plug 26 is in position in the sleeve 20, the head 27 of the pin 25 abuts against. the tace 26 of the button 22. To hold the but-ton 22, pin 25 and plug 26 in position in the tube 2() against movement, the sleeve surface just forward of the plug` 26 when in the position just described is termed into a rib 2S) by means of a. spinning operation thus maintaining the parts just described in position in the sleeve 2O against movement. A sleeve 30 of suitable conducting material is provided and upon which resistance unit 31 is wound, and consists of a plurality of turns of line insulated wire such as German silver. rllhe sleeve 30 is provided with an orifice 32 el a size to permit .it being slipped over the pin 25 and is attached to the forward end of the pin 25 by means o't a so'lt solder or similar easily fusible alloy or metal. @ne end of the unit is soldered to the pin 25, while the other end of the unit is soldered to the sleeve 20. rlhe solder used in mal:- ing the connection between the pin 25 and sleeve 30 may be any sott alloy melting at about 160O and the solder used in soldering the terminals of the unit 31 to the pin 25 and sleeve 2O respectively is comparatively hard.

F ig. 2 represents an enlarged partial view showing the heat coil il in supported inv operative position between the springs 5 and 6. The spring 15 is provided with an orifice 35 through which the end 36 oil the pin 25 extends, and the stud n3 ot the button 22 rests in the slot 3? in the tip 17 or the spring 6. The spring 6 is under tension and when the heat coil A is in position as just described, the sleeve 30 upon which the unit 31 is wound abuts against the iace otl he spring 15 and the end 36 el the pin 25 engages the spring 5. The circuit e1;- tends 'from the spring 5, through the pin to the terminal Li0 et the unit 31, the winding ot the unit 31, the terminal Ll1 of the unit 51, the sleeve 20, spring 6 to Vthe conductor 7. lVhe-n a dangerous current oi' the character described traverses the line for a sutiicient length of time, the resistance of the coil or unit 31, causes the development oit heat, which is communicated to the sleeve 30 and acts upon the sott solder whicn holds the sleeve 30 in place upon t-he pin 25 under normal conditions. In a short time this solder becomes softened and yields to the force exerted by the spring 6 which forces the sleeve 20 to the right and the pin 25 is also moved, the said pin 25 sliding through the sleeve 30. The end 36 ol' the pin 25 being in engagement with the spring 5 'lorces its angular portion into engagement with the plate 2 thereby grounding the incoming line conductor and the conductor extending to the switchboard.

lVhile l have illustrated the heat coil o my invention in association with a. speciiic 'form of apparatus, l wish it understood that it is adapted to be used in connection with other apparatus, and l also do not wish to be limited` to the exact structure as shown, as changes may readily suggest themselves to those skilled in the art, but aim lto cover all such changes and modifications as come within the spirit and scope of the appended claims.

`What l claim as new and desire to secure by United States Letters Patent, is as iol lows:

1. A protective appliance of the character described including a cylindrical tube oi conducting material having an internal ridge, a pair oit discs engaging said tube and secured therein by said internal ridge, a pin of conducting material insulatingly vfastened within said tube by said pair oif discs and Xtending therefrom, a member integrally formed with one of said disks and adapted to protrude through au openingl in said tube, a fixed member and a flexible member Jor supporting said protective appliance, said flexible member adapted to receive one end ot said pin to` support said protective appliance in position and a coil of wire mounted upon said pin having its one end. electrically connected to said pin and its other end' electrically connected to said tube, said pinv being included in circuit with said tube and said coil of wire in series.

2. A protective appliance of the character described including a cylindrical tube of conducting material having an internal ridge, a pair of discs engaging said tube and secured therein by said internal ridge, a pin of conducting material insulatingly fastened within said tube by said pair of discs and extending therefrom, a. sleeve slipped over said pin and secured thereto by a soft alloy, and a coil wound upon said sleeve having its one end attached to said pin and its other end secured to said tube, said pin being included in circuit with said' coil and said tube in series said coil being adapted when an abnormal current passes therethrough to melt said alloy thereby permitting said sleeve to slide along said pin.

3. A protective appliance of the character described including a tube of conducting material, an interna-l ridge integrally formed in said tube, a disc of insulating material having an orifice and adapted to iit into said tube in juxtaposition to said ridge, a pin of conducting material provided with an enlarged. end portion and adapted to extend through the orificeV in said disc, a second disc of insulating material adapted to be placed in said tube to abut against the head of said pin to hold the same in position, said disks and said pin being held in position in said tube against displacement by said internal ridge, a member integrally formed with said second disk and adapted to protrude through an opening in said tube, and means for engaging said protruding end and the other end of said pin tor operatively supporting said protective appliance in position.

fl. A protective appliance of the character described, including a cylindrical tube having a portion of one end turned over, a disc of insulating material adapted to lit into said tube and abut against said turned over end portion, a second disc having an orilice and adapted to tit into said tube, a pin provided with an enlarged end portion and extending through the orifice in said second disc and having its enlarged end portion abutting against said first disc, means including an internal ridge formed integrally with said tube for securing said second dise in position whereby said discs and pin are firmly secured in said tube against displacenient, a. member integrally formed with said tirst disk and adapted to protrude through an opening in the turned over end of said tube, and means for engaging the protruding end of said member and the other end ot said pin for operatively supporting said protective appliance in position.

5. A protective appliance of the character described including a cylindrical tube having a portion of one endturnedk over, a disc of insulating material having an oriiicey and adapted tofiit into said tube andv abut against means including an internally raised portion formed integrally with said tube, a pin provided with an enlarged end portion and extending through the orifice in said disc, a second disc adapted to tit into said tube and abut against the enlarged end portion of said pin and also to abut against the said turned over end portion of said tube whereby said discs and pin are firmly supported in said tube against forward movement by said means, a coil secured to said pin having its one end electrically connected with the pin and its other end electrically 'connected with said tube, and a projecting portion for said last disc for use in securing the protective appliance in position.

6. A protective appliance of the character described including a cylindrical tube, a disc of insulating material having an orifice y and adapted to lit into said tube and abut against means consisting of a ridge formed integrally with said tube, a pin provided with an enlarged end portion and extending through the orifice in said disc, a second disc adapted to tit into said tube and abut against the enlarged end portion of said pin, means including a circumferential shoulder formed integrally with said tube for securing said second disc in position whereby said discs and pin are firmly supported in lsaid tube by both of said means, a sleeve of conducting material adapted to be slipped over said pin and means consisting of a soft alloy securing said sleeve to said prin, a coil mounted upon said sleeve having its one end electrically connected to said pin and its other end electrically connected to said tube, and an integrally formed projecting stud i''or said second disc for use in securing the protective device in position.

7. A protective appliance ot the character described including a cylindrical tube, a disc of insulating material having an oritice and adapted to iit into said tube and abut against means including a ridge formed integrally with said tube, a pin provided With an enlarged end portion and extending through the oriiice in said said disc, a second disc adapted to tit into said tube and abut against the enlarged end portion of said pin, means including a turned over end portion formed integrally with said tube for securing said second disc in position whereby said discs and pin are lirmly supported in said tube against movement 'by both of said means, a sleeve of conducting material adapted to be slipped over said pin and means including a sott alloy securing said sleeve on said pin,

a coil mounted upon said sleeve having its one end electrically connected to said pin and its other end electrically connected to said tube, and an integrally lorined project- 5 ing stud for said second disc for use in securing the protective device in position, said device when in position adapted to be yieldingly held under spring tension so that when the said soft alloy is fused the said sleeve slides along said pin, thereby permitting a change in the circuit in which said appliance is connected.

Signed by Ine at Chicago, county of Cook and State of Illinois, this 12 day of April,

HIRAM D. CURRIER. 

